Manual reset mechanism for overload relays



y 6, 1968 K. L. PAAPE ETAL 3,392,593

MANUAL RESET MECHANISM FOR OVERLOAD RELAYS Filed April 25. 1966 INVENTOR. KENNETH L. PAAPE y DONALD s. sue/w United States Patent 3,392,593 MANUAL RESET MECHANISM FOR OVERLOAD RELAYS Kenneth L. Paape, Wauwatosa, and Donaid S. Bugni, Milwaukee, Wis., assignors to Square 1) Company, Park Ridge, 11]., a corporation of Michigan Filed Apr. 25, 1966, Ser. No. 544,900 11 Claims. (Cl. 74-110) ABSTRACT OF THE DHSCLOSURE Manual reset button mechanism which can be assembled in various configurations and dimensions for manually resetting one or more electrical overload relays from outside enclosures of various sizes Within which the relays are mounted in various special relationships.

This invention relates to reset mechanisms for manually resetting one or more electrical overload relays, or the like, from the outside of an enclosure within which the relays are mounted, and more particularly to a system of reset mechanism parts capable of being grouped to form various reset mechanism kits each usable to construct a plurality of reset mechanisms.

Electromagnetic starters for electric motors are provided with one or more overload relays and are commonly mounted within metal enclosures. Each relay usually has a plunger which must be depressed against a spring bias to reset the relay after the relay has opened as a result of a fault or overload. There are generally two, and often three, overload relays per starter, and there may be one or more starters within an enclosure. Unless a reset mechanism is used, the overload relays of a starter can be reset manually only by opening the door of the enclosure and depressing the appropriate plungers individually.

Because the reset plungers of the overload relays of modern motor starters may be depressed at any time without adverse effect, reset mechanisms have been provided which are operable to depress the plungers of all of the overload relays from the outside of an enclosure even though not all of the relays need to be reset. It is readily apparent that there are a wide variety of possible locations of overload relays within enclosures both with respect to each other and to the doors and Walls of the enclosures. For example, the enclosures vary widely in size, and the reset plungers of the overload relays are variously located on the starters which may be of different types and horsepower ratings. Heretofore, in order to provide for manual resetting of overload relays from the outside of an enclosure, it has been necessary for the starter manufacturer to design and build a separate reset mechanism for each different spatial arrangement of reset plungers encountered.

It is an object of the present invention to provide a system of reset mechanism parts capable of being grouped to form various reset mechanism kits, each kit being usable to construct a plurality of different reset mechanisms each manually operable from the outside of an enclosure to reset overload relays having their reset plungers in a specific spatial arrangement within the enclosure.

Another object is to provide a reset mechanism. which can be adapted readily for manually resetting overload relays from outside enclosures of various sizes within which the relays are mounted in various spatial relationships.

Another object isto provide a system of reset mechanism parts for constructing an overload relay reset mechanism in which the linear travel of a manual operating means exposed outside of an enclosure is translated 3,392,593 Patented July 16, 1968 into linear travel of one or more actuating members of adjustable length and positionable at adjustable distances from each other and the operating means so as to permit its use to reset overload relays variously spaced within enclosures of various sizes.

Further objects and advantages of the invention will be readily apparent from the following specification wherein reference is made to the drawings, in which:

FIG. 1 is a side view of a starter enclosure with part of an enclosure wall and the door broken away to show a reset mechanism constructed from a system of parts in accordance with the present invention;

FIG. 2 is a top sectional view taken the line 2-2 of FIG. 1;

FIG. 3 is a perspective view of a typical group of reset mechanism parts of the system of parts in accordance with the present invention partially assembled into a reset mechanism and adapted for use as shown in FIGS. 1 and 2;

generally along FIG. 4 is an exploded perspective view of a different reset mechanism constructed from the system of reset mechanism parts;

FIG. 5 is an enlarged sectional view of a pushbutton operator assembly of the system of reset mechanism parts; and

FIG. 6 is a view showing the opening in the door which receives the operator assembly of FIG. 5.

Referring first to FIGS. 1 and 2, a typical enclosure 10 for electrical equipment has a vertically hinged door 11 and contains a motor starter 12 provided with a plurality of overload relays 14 having respective reset plungers 15.

A reset mechanism 16 constructed from a group of parts of a reset mechanism system in accordance with the present invention so as to be suitable for the particular application of FIGS. 1 and 2 is installed in the door 11 and is operable when the door 11 is closed to depress all of the reset plungers 15 thereby to reset any of the overload relays 141 which might be in their tripped positions. The reset mechanism 16 as shown in FIGS. 1 and 2 comprises a pushbutton operator assembly 18 mounted on the door 11 and having a pushbutton plunger 19 biased outwardly by a spring 20 (FIG. 5), and a plurality of actuating members 21 carried by a cross bar 22 and properly positioned along the cross bar and of the proper length to engage the reset plungers 15, respectively.

In operation of the reset mechanism 16, depression of the pushbutton plunger 19 against the force of the spring 20 results in translation of the linear movement of the pushbutton plunger 19 into like travel of the actuating members 21 from the initial position shown thereby to depress the reset plungers 15 against the bias of their respective return springs (not shown).

The force of the spring 20 and the force of the return springs of the reset plungers 15 restores the reset mechanism 16 to its initial position when the depressing force on the pushbutton plunger 19 is diminished isufiiciently.

A reset mechanism similar to the reset mechanism 16 of FIGS. 1 and 2 but with the actuating members 21 not foreshortened, as will be described, is shown in FIG. 3. Each of the actuating members 21 comprises a connecting rod 23 and an actuating head 24, and each of the connecting rods 23 is threaded throughout its length and at one end preferably has a relatively short portion 25 of reduced diameter. The actuating heads 24, shown best in FIG. 4, are each molded of one piece of insulating material and each has a circular disc-shaped actuating portion 26 coaxial with a relatively long hexagonal nut portion 28. A threaded opening 29 extends axially through the portions 26 and 28 and receives in threaded engagement an unreduced end portion of one of the connecting rods 23.

Although in the present embodiment the openings 29 extend completely through the actuating heads 24, they may terminate short of the outer face of the disc-shaped portion 26 provided they are long enough to provide the required adjustment as will he described.

The cross bar 22 is of L-shaped cross section to impart rigidity and has a rectangular opening 30 at its longitudinal midpoint extending through its wider wall, and has, on each side of the opening 30, a group of openings 31 through the wider wall. The openings 31 of each group are preferably uniformly spaced with respect to each other longitudinally of the cross bar 22.

As shown best in FIG. 5, the pushbutton operator assembly 18 comprises the pushbutton plunger 19, the spring 20, an inner housing 34, an outer mounting and guard ring 35, and a sealing gasket 36. The pushbutton plunger 19 has a relatively long neck portion 38, meter ably of square transverse cross section thereby to prevent undesired rotation, and a reduced end portion 39, also of a nonrotatable cross section, shown rectangular, defining a pair of shoulders 40. The length of the reduced end portion 39 is preferably slightly less than the thickness of the wall of the cross bar 22 immediately surrounding the opening 30. A threaded, counterbored opening 41 extends axially through the end portion 39 into the neck portion 38 a sufficient distance to accommodate selectively the threaded portions of a shoulder bolt 42 or the reduced end portion 25 of one of the connecting rods 23.

The assembly 18 ordinarily is nonrotatably mounted in an opening 44 in a front panel or door of an enclosure, such as the door 11 of the enclosure 10. To this end, a reduced neck portion 34a of the main housing 34 is nonrotatably installed in the opening 44 from the inside of the door 11 with a suitable projection extending from the neck portion 34a received in a notch 44a (FIG. 6) in the peripheral edge of the opening 44. When the neck portion 34a is thus nonrotatably installed in the opening 44, the guard ring is threaded upon the portion 34a extending externally of the door 11. When the ring 35 is thus tightened, the marginal area of the door 11 immediately surrounding the opening 44 will be sandwiched between the ring 35 and the gasket 36 which overlies a flange 45 of the main housing 34. The inner housing 34 has a relatively long guide portion 46 having an axial square opening accommodating the neck 38 of the pushbutton plunger 19. The guide portion 46 supports the pushbutton plunger 19 and permits free but guided movement of the plunger 19 despite the plunger 19 being loaded with the weight of the remainder of the reset mechanism as will be explained.

One of the various reset mechanism kits made up parts of the system may include one of the pushbutton operator assemblies 18, one or more actuating heads 24, one or more connecting rods 23, one of the cross bars 22, one of the shoulder bolts 42, a plurality of large nuts 48a and small nuts 48b, a washer 49 shown in FIG. 4 having a rectangular opening, and a common washer 50.

The threaded opening 41 in the end of the push-button plunger 19 accommodates either the shoulder bolt 42 or the reduced portion 25 of one of the connecting rods 23. This feature permits reset mechanisms of three general configurations to be constructed from the kit just described.

When one or more connecting rods 23 are required with none of the rods 23 in alignment with the operator assembly 18 as in FIG. 3, the cross bar 22 is connected to the pushbutton plunger 19 by means of the shoulder bolt 42, the short rectangular portion 39 of the pushbutton plunger 19 fitting into the like shaped opening 30 in the cross bar 22 with the shoulder bolt 42 in combination with the washer 50 forcing the cross bar 22 against the shoulder 40 of the plunger 38 as the bolt 42 is tightened in the opening 41 of the plunger. In this first configuration, the connecting rods 23 are connected at desired locations along the cross bar 22 by insertion of their short reduced end portions 25 into selected ones of the openings 31 and are fastened with nuts 48b as indicated. A single nut 48b may be used for each connection of a connecting rod 23 to the cross bar 22 with a shoulder, defined by the reduced portion 25, abutting the cross bar 2 against the side opposite from that in contact with the nut 48b. Alternatively, a pair of the nuts 48!), one on each side of the cross bar 22, may be used for each of the connections.

For a second configuration, wherein a plurality of the connecting rods 23 are required with one of the rods 23 in alignment with the operator assembly 18, the reduced portion 25 of one of the connecting rods 23 in combination with one of the nuts 48b and one of the washers St} is used in place of the shoulder bolt 42 and the washer 50 as in the second configuration. The other connecting rods 23 in the second configuration are connected at desired locations along the bar 22 as in the first configurat1on.

When only one connecting rod 23 is required and the pushbutton operator assembly 18 can be mounted in alignment with a reset plunger 15, a reset mechanism of a third general configuration as shown in FIG. 4 may be assembled with one of the connecting rods 23 threaded directly into the opening 41 of the pushbutton plunger 19, preferably with the washers 49 and 50 and one of the nuts 48b, the washer 49 slipping over the reduced end portion 39 to insure proper positioning of the pushbutton plunger 19 with respect to the guard ring 35 in the released position.

In each of the three configurations, the ends of the connecting rods 23 opposite the reduced end portions 25 screw into the like-threaded openings 29 of respective ones of the actuating heads 24 with respective nuts 48a used to secure the assembly after final adjustment.

The centers of the openings 30 and 31 in the bar 22 are spaced apart a distance not greater than the width of the disc-shaped actuating portions 26 of the actuating heads 24 so that the range of positions of the actuating portions 26 is continuous. In the preferred embodiment, the discshaped portions 26 are one inch in diameter and the openings 31 of each group are spaced one-half inch between centers.

The connecting rods 23 have uniformly spaced circumferential grooves 51 throughout their length, excepting the short reduced portion 25, which allow the rods 23 to be easily shortened without damage to the threads. The grooves 51 are spaced at intervals less than the length of the threaded openings of the actuating heads 24 to provide a continuous range of distances between the actuating heads 24 and the cross bar 22.

The actuating heads 24 are also designed with actuating portions 26 sufficiently broad so that, in some instances, a single actuating member 21 may be used to actuate more than one reset plunger. It is to be noted that in the depressed position of the pushbutton plunger 19, when the actuating heads 24 are in engagement with the reset plungers 15, there is no direct met-al-to-metal contact between any of the rods 23 and the pushbutton operator assembly 18.

We claim:

1. A system of nonfunctionally equivalent parts capable of being grouped in various quantities into kits from which parts can be selected to build one or more reset mechanisms of various configurations and dimensions for manually resetting overload relays from outside enclosures of various sizes within which the relays are mounted in various spatial relationships, said system comprising a pushbutton operator assembly having a reciprocable pushbutton plunger and means for constraining the operator in relation to an enclosure at an opening therein so that an inner end portion of the plunger is within the enclosure and an outer portion of the plunger is exposed outside of the enclosure to permit manual reciprocation of the plunger from outside the enclosure, a cross bar, means for rigidly securing the cross bar on the inner end portion of the plunger transversely of the axis of the plunger, an actuating head having an actuating surface, a connecting rod, means for removably securing the connecting rod at one end portion to the cross bar at predetermined spaced locations thereon, selectively, with the connecting rod extending away from the cross bar oppositely from the plunger and parallel to, or in alignment with, the axis thereof, the actuating head and the connecting rod having mutually engaging means for mounting the actuating head on the other or free end portion of the connecting rod so that its actuating surface is adjustably positionable at selected locations within a predetermined range of distances from the cross bar.

2. The system of parts of claim 1 characterized in that provision is made for shortening the connecting rod in finite steps of length, and the range of adjustment of the actuating head along the free end portion of the rod after such shortening is equal to or greater than the length of the largest of said steps.

3. The system of parts of claim 1 characterized in that said actuating surface extends in a direction parallel to the cross bar for a distance not less than the distance between adjacent ones of said spaced locations.

4. A reset mechanism for manually resetting, from outside an enclosure, a plurality of overload relays mounted within the enclosure, said mechanism comprising a pushbutton operator assembly having a reciprocable pushbutton plunger and a guide for the plunger permitting guided linear reciprocation of the plunger, a cross bar, means for securing the cross bar to an end portion of the plunger transversely thereof, a plurality of actuating heads having respective actuating surfaces, and a plurality of connecting rods, the cross bar and each of the connecting rods having mutually cooperating attachment means for securing end portions of the connecting rods to the cross bar at predetermined spaced attachment locations therealong, selectively, with each connecting rod extending away from the cross bar oppositely from the pushbutton and parallel to the axis thereof, each of the actuating heads and each of the connecting rods having mutually engaging means for mounting the actuating heads on the connecting rods, respectively, at the free end portions of the connecting rods remote from the cross bar, and the engaging means permitting each actuating head to be adjusted longitudinally of its associated connecting rod.

5. A reset mechanism as claimed in claim 4 characterized in that provision is made for altering the length of the connecting rods.

6. A reset mechanism as claimed in claim 4 characterized in that the means for securing the cross bar to the plunger is operable to secure the plunger to one of the connecting rods in end-to-end coaxial relationship therebetween.

7. A reset mechanism as claimed in claim 4 characterized in that the spacing between the adjacent attachment locations along the cross bar is less than the width of the actuating heads measured in a direction from one of the connecting rods to another.

3. A reset mechanism as claimed in claim 4 characterized in that the connecting rods are threaded substantially throughout their length, and each of the mutual engaging means includes the threaded free end portions of one of the connecting rods and a complementary threaded opening in one of the actuating heads.

9. A reset mechanism as claimed in claim 8 characterized in that the means for securing the plunger to the cross bar comprises a threaded stud, a noncircular end portion of the plunger, a complementary opening in the cross bar for receiving the noncircular end portion, and a threaded axial opening in said end portion of the plunger for receiving, selectively, the threaded stud and an end portion of one of the connecting rods.

10. A reset mechanism as claimed in claim 4 charac terized in that said operator assembly includes a spring biasing the plunger to a retracted position in the guide wherein the cross bar engages the guide.

11. A reset mechanism as claimed in claim 8 characterized in that provision is made for shortening each of the connecting rods in finite steps of length, and the threaded opening in the actuating head is equal to or greater than the longest of said steps.

References Cited UNITED STATES PATENTS 3,142,732 7/1964 Clarke et al ZOO-116.2

FRED C. MATTERN, 111., Primary Examiner. W. S. RATLIFF, Assistant Examiner. 

